Emacs and XDG Base Dir Spec was: persistent storage for Emacs packages

[Thomas Koch]

There is a "standard" where to place different kind of files inside a users 
home 
directory[1], in short:

config: ~/.config/$APPNAME/
cache: ~/.cache/$APPNAME/
data: ~/.local/share/$APPNAME/

Unfortunately the standard does not yet include a place for STATE data[2].

It would be nice, if emacs would also use this "standard". This would make it 
much nicer to keep the emacs config in version control without an elaborate 
ignore file. Some people like me also keep their ~/.cache in a ramdisk[3].

[1] http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
[2] https://wiki.debian.org/XDGBaseDirectorySpecification#state
[3] https://github.com/xtaran/unburden-home-dir